Nut threading machine



April 26, 1938.

J. WERNER ET AL.

NUT THREADING MACHINE Filed Aug. 18, 1936 ll Sheets-Sheet l 5 ll 7Z0 QHumm- M \NVENTOR MSW ATTORNEYS April 26, 1938. J. WERNER ET AL 2,115,599

NUT THREADING MACHINE Filed Aug. 18, 1936 ll Sheets-Sheet 2 ATTORNEYSApril 26, 1938. J.'WERNER ET AL v2,115,599

NUT THREADING MACHINE Filed Aug. 18, 1936 11 Sheets-Sheet 5 ATTO R N EYSApril 26, 1938. J. WERNER ET AL ,5

NUT THREADING MACHINE ATTORN EYS \NVENTQR J. WERNER ET AL NUT TI READINGMACHINE April 26, 1938.

Filed Aug. 18, 1936 11 Sheets-Sheet 5 April 26, 1938. J. WERNER ET ALNUT THREADING MACHINE Filed Aug. 18, 1956 ll Sheets-Sheet 6 \NVENTOR Y 5BY y) W ATTORNEYS p 1938. J. WERNER ET AL 2,115,599

NUT THREADING MACHINE Filed Aug. 18, 1936 ll Sheets-Sheet 7 April 26,1938. J. WERNER ET AL NUT THREADING MACHINE Filed Aug. 18, 1 956 11Sheets-Sheet 8 INVENTOR fig ATTO NEYS April 26, 1938.. J, WERNER ET AL2,115,599

NUT THREADING MACHINE Filed Aug. 18, 1936 ll Sheets-Sheet 9 April 26,1938.

J. WERNER ET AL 2,115,599

NUT THREADI NC: MACH INE Filed Aug. 18, 1936 ll Sheets-Sheet 1O :1 A249. h lfiifi 4 0.4 jg Y W W INVENTOR /?6) 7 3*?7 April 26, 19 38. .1WERNER ET AL 2,115,599

NUT THREADING MACHINE Filed Aug. 18.1936 11 Sheets-Sheet 11 zam 566 2626zaaia INVENTQR Y YEFM? Patented Apr. 26, 1938 UNITED STATESPATENTOFFICEV NUT THREADING MACHINE Joseph Werner, Detroit, Mich, andGeorge Kroupsky, New York, N. Y., assignors, by mesne assignments, toThe Waterbury Farrel Foundry and Machine Company, Waterbury,

* Conn, a corporation of Connecticut Application August 18, 1936, SerialNo. 96,634

13 Claims. (Cl. -133) The invention relates to a machine for tappingtherefrom are supplied with a sufllcient bulk of or cutting female screwthreads in a previously cutting oil to rapidly carry them away. formedopening, and relates more particularly to t I. To prevent the momentumof some of the a nut tapping machine of the straight tap type freemoving nuts from moving them an undue 5 for tapping the cylindricalbores of nut blanks distance rearwardly to a danger point where they 5so as to form finished, threaded nuts. would do damage, and at the sametime permit- The objects of the invention are: ting all of the nuts tobe moved past this danger A. To provide an improved means for pushingpoint at a time, in synchronism with the rest of the nuts one at a timefrom the supply means the machine, when there is no dang r. in throughthe front part of a rotatable chuck and J. To positively ensure that nonuts will be 3.0- m out the front end of the threaded portion or bitcidentally p n d und r either of the pairs of of a tap, in such mannerthat the nuts are adpp jaws w en the latter close upon the vanced bysaid pusher with extreme accuracy Shank of the tap. which is notappreciably affected by the clearanct v K- To positively p t theStripping fi e 15 or wear of the various parts. from closing at a p intadja t th tap s p- 15 B. To at first very rapidily push the nuts sucpingJ'aWS. e cept when said jaws are open and cessively from the supplymeans to the front nd when, therefore, it is safe to move the nuts alongof the bit of a tap, and to thereafter push each the tap pa t d pp l nutat a much slower, but very accurately conp ov de an imp d ea of,clflsing .9 trolled rate of speed over said bit. e two pairs of pp j wc alternately. C. To provide a nut pushing mechanism which p the shankof the p 80 that, Said shank is capable of either positively pushingeach sucmay be y p w y ripp d even though v y cessive t from g l means tthe tap, or generous machinery tolerances in the dimensions optionallyapplying for a limited range of moveof the various parts are permittedor considerment a yielding pressure to said nut, in order to able Wearof the parts has taken p e. compensate for slight difference which mayex- To provide Such a Sh pe Of pp J' as ist between the lead of thecutters on the bit of will be t p s v in t n a d y t a n 'the tap andthe rate of movement of the nut With the a s Of the chuck.

pushen N. To provide a type of jaw which can be ad- 3 D. To provide apusher which will carry the J' t p p r p t e sh of a tap v n oblique,longitudinal thrust of the pusher cam in though Said Shank be somewhatbent. a most effective manner and also prevent said T0 permit the use Ofp vetal connectionto pusher from cocking laterally. drive the strippercarriage from the cross shaft, E. To provide a type of chuck which willposiv n though said c rria as a nsi e ly tively'rotate the nut, and yetprovide'maximum long stroke and is located very close to said cross 35lateral freedom of movement of the nut.

T provide type of h k hi il be Numerous other ob ects of the inventionand capable of handling either hexagonal or square practical solutionsthereof are disclosed in detail t of any one th d i in the hereinspecification, wherein.

40 G. To provide a tap which will be so conthe a n g awi 4o structed asto permit a large quantity of cutting 1 1S a perspectlve 0f the machineas 1 sh awa the chi S as fast as a who1e, showing generally the locationof the 3 52 2 5: 23 2 the i by theilhreaded bit different devices whichform the subJect of this invention. IPI f Z ppw therear end of the nutturning Fig. 2 is a fragmentary, vertical, longitudinal chuck with aliberal quantity of cutting oil at a sectlon of the upper from part ofthe machine showing the chuck whereby the nuts are turned point insidethe chuck aws so that the tendency relatively to the bit of the tap, andone form hr of said jaws to throw said oil radially outward the meanswhereby the pusher is actuated for is impeded by the Inner faces of theJaws themcarrying the nut blanks from the feed device to selves, and tothereby enable a sufficient supply said chuck and tap,

of cutting oil to accumulate inside said chuck Fig. 3 is a vertical,longitudinal section of the j to ensure that the p and the ut be ngupper rear part of the machine, showing part of tapped are provided withan adequate quanone of the means whereby the nuts, after they 55 tity ofcutting oil and that the chips emanating are tapped, are separated onthe shank of the 55 operated solidly, or adjusted so as to impart 9.

limited amount of yielding thrust against the nut pusher during theinitial part of its stroke.

Fig. 5 is a vertical section, taken on line 5i, Fig. 4 and showing moreparticularly the means whereby the plunger, which actuates the pusher,is able to take the oblique, vertical thrust of the pusher cam, and isalso prevented from rocking sidewise, this being accomplished by rollerspivoted on opposite sides of the plunger and running on longitudinaltracks on the adjacent part of the main frame.

Fig. 6 is a sectional top plan view of the mechanism shown in Fig. 3,and taken in line 6-6, Fig. 3.

Fig. 7 is a vertical cross section, taken on line 1-1, Fig. 3 andshowing the first pair of tap gripping levers in an open position, alsothe wedge which actuates said first pair of gripping levers retractedfrom said levers, and the cam and associated parts for operating saidwedge and exerting a yielding thrust against the same.

Fig. 7a is a fragmentary, bottom plan view of the upper jaw of the firstpair of gripping levers, taken on line la-4a, Fig. 7, showing how thejaw block may be obliquely adjusted to enable the same to properlyengage with a bent tap shank.

Fig. 8 is a similar section, taken on line 88, Fig. 3 and showing thesecond pair of tap gripping levers in their closed position, in whichposition the flat face of the lower holding jaw engages with the fiatunderside oi the tap shank while the upper rounded side of this tap,shank is engaged by the semi-cylindrical, concave face of the companionupper jaw.

Fig. 9 is a vertical, longitudinal, section taken on line 3-9, Fig. 8and showing the eccentric or crank upon which the upper holding lever ofthe rear pair of gripping levers may be raised and lowered in order torelease the tap shank while the latter is released from the front pairof holding levers, this figure showing the stop arm on the eccentricpivot rod and the screw on the frame for. limiting the backward movementof said stop arm and thus preventing the thrust on the outer arm of thislever from aocidentallyrotating said pivot rod into an inoperativeposition.

Fig. 10 is a fragmentary cross section, taken on line ill-i0, Fig. 3 andshowing one pair of stripping fingers swung inwardly from the two legsof the stripper carriage and into a position in which they stand in thepath of a nut on the shank of the tap and are thus capable of movingthis nut lengthwise of! the tap shank and past the first pair ofgripping jaws.

Fig. 11 is a horizontalsection, taken on line ll-H. Fig. '7 and showingmainly the holding mechanism whereby the tap shank is alternatelygripped at two different points in the length thereof, and also part ofthe means for dividing the nuts which are on the tap shank after leavingthe bit and feeding them one or more at a time to a position in front ofthe first pair of gripping levers and also a part of the means forstripping the nuts from the tap shank and moving the same past thegripping levers.

Fig. 12 is a longitudinal section, taken on line l2--I2, Fig. 11 andshowing the gripper operating wedges in square form, and also the pinand slot connection and the spring means associated therewith.

Fig. 13 is a vertical section. taken on line 13-", Fig. 7, showing theform of one of the clutch disks or plates whereby the power isautomatically thrown 01! in the event that the machine becomes stuck, soas to avoid breaking of the machine.

Fig. 14 is an enlarged fragmentary section, taken on line l4--l4, Fig.13 and showing one of the clutch balls engaging with companion 'recesseson the two clutch plates, one recess being deep and adapted to retainthe ball at all times while the other recess is shallow and adapted tobe disengaged from the respective clutch ball.

Figs. 15-19 are diagrammatic top plan views of the main elements of thestripping mechanism whereby the tapped nuts are moved step by step pastthe two pairs of gripping levers which hold the tap. These figures alsoshow part of one form of the dividing mechanism which operates to divideor separate some of the nuts from the row of nuts, which has accumulatedon the shank of the tap after passing the bit of the tap, and advancessaid nuts within reach of the nut stripping mechanism.

Fig. 20 is a fragmentary, sectional, top plan view, similar to Fig. 6but showing a modified form of dividing finger, taken on line, 23-33Fig. 21.

Fig. 21 is a fragmentary, vertical, longitudinal section thereof.

Fig. 22 is a fragmentary, vertical, transverse section thereof, taken online 22-23, Fig. .21.

Figs. 23-2'7 are diagrammatic top plan views, similar to Figs. 15-19,but showing the nut stripping mechanism in combination with a modifiedform of nut dividing means, whereby the nuts are advanced along theshank of the tap from the rear of the threading bit of said tap to thefirst pair of gripping levers and into the path of the first pair ofstripping fingers.

Fig. 23 is a fragmentary, vertical, longitudinal section, similar toFig. 2, but showing a modified form of cam and associated mechanism foradvancing the nut pusher positively and retracting the same by springpressure.

Fig. 29 is a vertical, transverse section of the same, taken on line39-23, Fig. 28.

Fig. 30 is a horizontal section, taken on line 3M3, Fig. 28, and showingmore particularly the means for vertically guiding the carriage, whichcarries the two cams whereby the nut pusher is moved forwardly, and alsothe springs for lowering this carriage.

.Fig. 31 is a top plan view of the splined connection between thedriving shaft which is shown in Fig. 29 and the movable member of theclutch forming part of the pusher actuation mechanism.

Fig. 32 is a vertical transverse section, taken on line 32-32, Fig. 29,showing in detail the clutch whereby the driving shaft is connected withand disconnected from the gear pinion which meshes with the gear rack ofthe pusher operating mechanism.

Fig. 33 is a fragmentary vertical longitudinal section, corresponding toFig. 3 and showing a lever mechanism for actuating the strippercarriage.

Fig; 34 is a horizontal section thereof, taken on line 34-34, Fig. 33.

Fig. 35 is a vertical transverse section of said stripper actuatingmechanism, taken on line 35-35, Fig. 33.

Fig. 36 is a rear end elevation, on an enlarged scale, of a modifiedform of driving chuck, taken on line 36-46, Fig. 37.

Fig. 37 is an oblique, longitudinal section thereoi, taken on line31-31, Fig. as.

, Fig. 38 is a rear end elevation, on an enlarged scale. of stillanother modified form of driving chuck, taken on line 3838 Fig. 39.

Fig. 39 is an oblique, longitudinal section there- 01', taken on line39-39, Fig. 38.

In its general organization the present invention of the form shown inFigs. 1-19 includes a hopper 59 which is periodically filled with asupply of nut blanks 51, and from which hopper said nut blanks slidedown through an alignment channel 60, and are pushed rearwardly, one byone, from the open lower end of said channel by a pusher 8| into arotating, driving chuck 55. While thus being rotated by said chuck, eachsuccessive nut blank continues to be pushed by said pusher SI, and isthereby caused to move into engagement with the threaded bit 58 of astraight shanked tap. This causes said nut blanks to be threaded, andthe resulting threaded nuts 2 then accumulate on the shank 95 of thetap. Successive groups of these threaded nuts (for instance group I96)are then moved rearwardly by a dividing finger iii which is pivoted atHll to a rock arm I08 and is indirectly actuated by a carriage I25 whichreclprocates in the tail stock I94 of the machine. A primary pair ofstripping fingers I93, I94 pick up the group of nuts i95 which have beenmoved forwardly by the dividing finger I I I and move them past a pairof primary tap gripping jaws Nil, l82 which at this time are open butintermittently grip the shank 95 of the tap to restrain said tapagainstboth rotary and longitudinal movement. In a similar manner and in propersynchronism with the rest of the machine, a pair of secondary strippingfingers l93a, l9fla move the group of nuts H96 past a secondary pair ofgripping jaws Mia, I92a and push them off the rear end of the shank 95of the tap, where they fall down a chute i911 and are thence removedperiodically from the machine.

Detailed description of threading mechanism Journaled horizontally andlongitudinally in the front part of the main frame ll) of the machine isa drive shaft M, as best shown in Figs. 1 and 2. This drive shaft may bedriven in any suitable manner as, for instance, by the electric cientlylow rate of speed by being suitably belt driven by the belt 41 from thedrive shaft M.

The rear end of said drive shaft 4| is suitably secured to a drivingsprocket 48, preferably of the gear toothed, silent chain type, aroundwhich is passed the lower end of a silent chain belt 50. The upper endof said chain belt passes around a driven sprocket 5| which isintegrally formed on the periphery of a rotary driving head 52. The

latter is preferably journaled on a single ball bearing 53 in a bearinghousing 54 which is suitably connected to the main frame of the machine.Screwed into the bore of said rotary driving head 52 is a driving chuck55 having a plurality of rearwardly extending driving arms 56 which areadapted to engage with the corners of a succession of nut blanks 51 andto rotate said blanks relatively to the threaded bit 55 of a straightshanked tap.

These nut blanks 51 are poured into the hopper 59 of the machine, andslide down by gravity through a vertical alignment channel 60, the lowerrear end of which is open to permit the lowermost nut blank to be pushedrearwardly through the bore of the chuck 55 and upon the front end ofthe threaded bit 58 of the tap. This rearward movement of eachsuccessive nut blank is effected by a pusher 6| which is actuated asfollows:

Secured to an intermediate part of the drive shaft II is a worm 62 whichmeshes with a worm wheel 53 secured to a jack shaft 65 which isjournaled horizontally and transversely in the main frame of themachine. This worm and worm wheel power connection cause said jack shaft64 to rotate very considerably slower than the drive shaft 4| Secured tosaid jack shaft 64 is a spur gear 65 which meshes with a spur pinion 66mounted on an intermediate shaft 61 suitably journaled horizontally andtransversely in the main frame 40 of the machine. This spur pinion 66,in turn, meshes with a cam-driving, spur gear 68 which is secured to acam shaft 69 that is Journaled horizontally and transversely of themachine and has secured to its central part a heart shaped cam 10. Thesegears 65, 68 and intermediate pinion 55 merely serve to transfer thepower from the jack shaft 64 to the cam shaft 89 without any change ofspeed.

Said cam 10 contacts with and actuates an anti-friction roller M whichis journaled on a horizontal cross pin 12 (see Fig. 4) and the latter issecured at its opposite ends in the forwardlyextending bifurcated arms113 of a pusher sleeve it. outwardly of the outer faces of the saidbifurcated arms 13, said cross pin 12 has journaled thereon asymmetrically disposed pair of guide, thrust roller: i5, which roll upona pair of guideways 16 formed horizontally and longitudinally on themain frame 40 of the machine.

It is to be noted that the central plane of the cam Hi intersects theaxis of the pusher BI, and also that the axis of rotation of said camintersects the axis of the pusher. Because of this construction themovement of the pusher will always be in exact accordance with thesurface of the cam which is at the moment in contact with the roller Hand this will be true irrespective of the clearance in or the wear ofthe various bearings which are associated .with this pusher mechanism.-In addition to this, the oblique thrust against the pusher sleeve 14 isreduced to the lowest practicable minimum, so that wear on said pushersleeve is reduced to the minimum.

In pusher mechanisms heretofore constructed, the various members havenot been in line with the axis of the pusher, and, as a consequence, theclearance in and the wear of the bearings has caused slack movementswhich have, in actual practice, been found to vary in the direction inwhich they act and to be not positively amenable to any type of controlbecause of the fact that the pressure exerted against the variousbearings vary considerably in their angle of thrust. In the presentinvention all angles of thrust remain substantially constant, and hencethe actuation of the pusher Si is very accurate even when the machinehas been in continuous service during a long period of time. It is to beunderstood that these matters are not particularly important whentapping, for instance, class 1 nuts which have large dimensionaltolerances, but they are very important when tapping class 4 nuts. Italso follows that such a construction as here disclosed and foundparticularly desirable for tapping fine tolerance nuts. can be employedto advantage in cutting large tolerance nuts. These rollers serve toboth take the oblique longitudinal thrust of the cam 10 against theroller Ii and to prevent the pusher sleeve 14 from cocking laterally asa consequence of the tendency of the rotational frictional contactbetween the rear face of the pusher II and the front face of therotating nut blank 51 'being tapped.

The rear end of the pusher sleeve I4 is coaxially bored out to receivethe cylindrical, large front end of the pusher I. Said pusher I and saidpusher sleeve 14 are prevented from rotating relatively to each other bya Pratt and Whitney type of countersunk key 11 which engages a keywayshaped spline 18 which is suitably formed in the bore of the pushersleeve 14. Said pusher sleeve is held laterally in alignment with thechuck II and with the threaded bit 58 of the,tap by having theperipheral surface of its rear end ll of cylindrical shape and slidablyreceived within a cylindrical guide ll formed in a guide block 02. Thelatter is secured to the main frame of the machine in any desiredmanner.

Secured to the front end of the pusher sleeve ll are a pair ofsymmetrical posts I! to the upper ends of which are secured a pair ofhorizontal longitudinal tension springs 84 (see Figs. 2, 4. and 5). Thefront ends of said springs are secured to a pair of hold-back pins 85which pass through suitable holes in the main frame of the machine andare restrained against rearward movement by a pair of cotter pins 88.

Thus, as the cam 'Hlrotates away from the position shown in Fig. 2, itthrusts the pusher sleeve 14 and the pusher 6| rearwardly and therebypushes the nut blank 51, which is at the bottom of alignment channel 60,rearwardly through the front part of the rotating driving chuck 55 andonto the front end of the threaded bit 58 of the tap.

As the nut blank passes into the front end of said chuck it is caused tobe turned in such a circumferential position as to be properly presentedto the arms 56 of the chuck. This operation is well known in the art andhas, therefore, been deemed not necessary to illustrate in the presentinvention.

After the nut blank has been pushed as far rearwardly as may have beenfound empirically to be expedient, the cam III, while continuing torotate in the one direction, returns to the position of Fig. 2, and thepusher sleeve H is thereby permitted to be retracted under the influenceof the tension springs 84. When this retractlve movement of the pushersleeves 14 occurs the pusher ii is also retracted.

It has been found highly desirable, in actual practice, to positivelyforce the nut blanks 51 upon the threaded bit 58 of the tap, so that themovement of said nut blank will be in exact accordance with the pitch ofthe threads of said threaded bit. On the other hand there may be, inactual practice, a very slight differential between the speed ofmovement of the pusher SI and the rotative speed of the chuck 55 (interms of the pitch of the threads of the threaded bit 56). Hence thepresent invention includes means whereby a very small, limitedresilience may be inserted between the pusher GI and pusher sleeve 14,this means being adjustable both as to the arrests amount of movementpermitted, and also the amount of tension imposed; The construction isas follows:

The intermediate part of the pusher 6| has rigidly connected thereto across bar 81. This connection is effected by reducing the diameter ofthe pusher to form the annular shoulder 88 and rigidly pressing saidcross bar 81 against said shoulder by a jamb nut 90 which is threadedonto the pusher at a point just rearwardly of said cross bar 81. Theouter ends of said cross bar receive the rear threaded ends of a pair ofsymmetrically arranged, horizontal, longitudinal, limiting tie rods 9|.The front ends of said tie bars are secured to the outer ends of thecross pin I2 located at the front end of and secured to the pushersleeve 14. Adjustably threaded on the central part of each tie rod Si isa tension adjusting nut 92, and received between the rear face of saidadjusting nut and the front face of the cross bar 81 is a compressionspring 83. Threaded onto the rear end of each tie rod is apusher-movement-limiting adjusting nut 94. When both of these nuts aredrawn up tight as shown in Fig. 4 the front face of the cross bar 81 isheld firmly against the rear end of the pusher sleeve ll.

Under these conditions the pusher Bi and the pusher sleeve 14 move as aunit, and there is no resilient connection between the cam 10 and thepusher 6| during the time that said pusher is being moved rearwardly.If, however, the adjusting nuts 94 are slacked off a certain desiredsmall amount, then, when said cam 10 starts to force the pusher sleeve14 forwardly, the pusher it will only be correspondingly actuated if theresistance to its movement is insufiicient to overcome the resistance ofthe compression springs 93.. If the rearward movement of the pusher isfaster than that required for the particular speed of rotation of thenut being tapped, in combination with the pitch of said nut, then thesprings 93 will give slightly, and will allow the nutblank to slightlylag behind the pusher Bi The adjustment of the spring tension of thesprings 93 is adjusted by adjusting the nuts 92.

After each nut blank 51' has been pushed a suflicient distancerearwardly upon the threaded bit 58 of the tap, further rearwardmovement of the nut blank is efiected by the threads which have alreadybeen cut in its bore. This causes each nut blank to continue to moverearwarclly (being turned meanwhile relatively to the threaded bit 58 bythe arms 56 of the driving chuck 55) until it drops off from thethreaded bit 58 onto the shank 95 of the tap, as best shown in Fig. 11.1

While the nut blank 51 is being pushed over the bit 58 of the tap, thethread cutting operation, which ensues produces a quantity of chipswhich should be removed just as fast as they are formed as otherwiseinaccuracies in the thread cutting are liable to result. In the presentinvention each nut blank is constantly supplied with a copious quantityof cutting oil at both its rear and its front face, supplied by thecutting oil pump 46.

The cutting oil to the rear face of the nut blank being threaded issupplied from an oil nozzle 96 suitably connected to said oil pump 46.This nozzle is so aimed that the cutting oil is fed in the space betweenthe inner faces of the arms 56 of the driving chuck 55 and theperipheral surface of the threaded bit 58 of the tap. The

aiming of this rear stream of cutting oil is eflec- I6 tive in that notonly is the stream of oil from said nozzle 96 not splashed laterally bythe arms 56 of the driving chuck but, on the contrary, any tendency ofthe cutting oil to pass out from this annular space within said arms 56is resisted by the inner faces of said arms. The consequence of thisresistance is that a considerable body of cutting oil pressure is builtup within said arms 56 and, in addition, the space within said armsliberally filled up with cutting oil. Ultimately, of course, thiscutting oil must escape, but this impeding of its escape enables a largequantity of cutting oil at high pressure to be driven against the rearface of the nut blank being tapped, and this solid body of oil enabledto carry away the chips bodily and at high speed as fast as they occur.As the centrifugal force of the driving chuck 55 throws outthis bodyofcutting oil with its chips, both said oil and said chips are caught byan annular trough 31 from whence they escape downwardly, under theinfluence of gravity, through a vent spout 96.

The cutting oil pump 46 also supplies a constant stream of cutting andcooling oil to a feed pipe I00 (see Figs. 1. and 2) whose upper end issecured to the main frame of the machine and conveys the cutting oilinto a flexible hose IN. The latter conveys the oil into the fronthollow end I02 of the pusher sleeve 14 from whence it flows rearwardlyinto the hollow bore I03 of the pusher6i and thence directly against thefront face of the nut being pushed rearwardly by said pusher over thethreaded bit 58 of the tap.

Nut dividing or starting mechanism Arranged at the rear end of themachine is a tailstoclr I04 which is longitudinally slidable on a pairof rail bars I05. The longitudinal position of said tail stock isadjustably regulated by means of a hand wheel I06 (see Fig. 3) which isarranged in the usual and well known manner to enable said tail stock tobe moved to whatever longitudinal position may be desired.

Pivoted at I01 to the'front upper corner of said ta-iistock is a rockarm I08. Pivoted at H0 in the lower end of said rock arm is a dividingor starting finger III which extends rearwardly and downwardly therefromand has its lower end or nose so shaped as to enable it to properlyengage with and push rearwardly such threaded nuts II2 as haveaccumulated on the shank of the tap just rearwardly of the threaded bit56 of said tap. The lower end or nose of this dividing finger III isconstantly urged downwardly into contact with the nuts by a tensionspring H3 whose front end is connected with a pin. II 4 extendingupwardly from said dividing finger III while its rear end is secured toa pin II5 projecting upwardly from the rock arm I08.

Adjustably secured by an adjusting head H6 and a set screw II1 to thecentral part of said rock arm I08 is a stop bar H8. The latter extendsdownwardly or forwardly from said adjusting head H6 and is adjustablyconnected at its lower end by a similar adjusting head I20 and set screwI2I with a stop arm I22. This stop arm is resiliently urged rearwardlyby a tension spring I23 whose upper end is connected with the projectingportion of said stop arm I22- while its lower end is secured to a pin I24 which projects horizontally forward from the front .transverse faceof the tail stock I04.

Horizontally and longitudinally slidably arranged in said tail stock I04is a stripper carriage I25 (see Figs. 15, 13, '1 and 8) which, as viewedfrom above, is of U shape having its legs I26 and I21 disposedhorizontally longitudinally and integrally connected together at theirrear end by a .connecting bar I28. The one leg I21 of this carriage isof plain rectangular form, while the other leg, I26, is provided at itsupper and lower faces with a pair of suitable, longitudinal side tonguesI30, I3I which engage with suitable longitudinal grooves in the tailstock and thereby prevent lateral displacement of the carriagerelatively to the tail stock.

Projecting laterally outward from the one leg I26 of said carriage I25and secured thereto by a pin I29 (see Fig. 8) is a stud I39 upon whichis journaled an anti-friction roller I32. This roller rolls in thecurvilinear track I33 (see also Figs. 3 and 6) of a sewing machine typeof cam I34. The latter rotates on a horizontal, longitudinal axis on ashaft I35 which is suitably journaled at its opposite ends on bearingsI36, I31 arranged in cross webs of the tailstock I04.

Secured to said shaft I35, forwardly of said cam I34, is a spiral pinionI38 which meshes with a spiral gear I40 secured to a driven cross shaftI4I The latter is suitably journaled horizontally and transversely inthe tail stock I04 in bearings I42, I 43 as best shown in Fig. 7.

This driven cross shaft MI is axially in line with a driving cross shaftI49 which is journaled transversely in the tailstock I04 in suitablebearings I44, I440 and I45. The one end of said driven cross shaft MI isprovided with a coaxial, fiat, driving tongue I46 which engages with adriving slot I41 cut transversely in the companion end of the drivingcross shaft I49. This tongue and slot connection affords a positivedriving connection between the driving cross shaft I49 and the drivencross shaft MI and yet permits certain assemblies of the machine to beremoved without necessitating the disassembly of both of said crossshafts.

Journaled adjacent one end of said driving cross shaft I49, on a bearingI48, is a driven sprocket wheel I50 around which passes the rear end ofa chain belt I5I. The front end of said chain belt passes around and isdriven by a driving sprocket wheel I52 (see Fig. 2) which is secured tothe jack shaft 64 previously described.

The driving connection between the drivensprocket wheel I50 (see Fig. 7)and the driving cross shaft I49 is of the non-positive type and isconstructed as follows:

Secured vcoaxially to the driven sprocket wheel I50 is a hub member I53in which (see Figs. 14, 13 and 7) are longitudinally and symmetricallydrilled a plurality of relatively deep retaining holes I54 each of whichcontains a driving ball I55. Similar but more shallow engaging holes I56are drilled into a driven collar I51. The latter is prevented fromrotating on the driving cross shaft I 49 by the provision of a splineI58, but is capable of sliding lengthwise thereon. Said driven collarI51 is resiliently urged toward the hub member I53 by a compressionspring I60,

' the tension of which is rendered adjustable by an adjusting nut I6Ithat is threaded onto the driving cross shaft I49.

By means of this construction, the driven sprocket wheel I50 is able tonormally drive the driving cross shaft I49. If, however, an accidentshould occur, and this driving-cross shaft I49 meets with undueresistance, then the driving balls I55 thrust the driven collar I51outwardly against the tension of the spring I60 and thereby disconnectthe power, and prevent breakage of the machine. When the pow.er is -thusdisconnected, said driven collar I51 is caused to jiggle back and forth,and this causes a sufllcient noise and clatter to call the attention ofthe operator to the fact that something is amiss. At the same time thereis no danger that the balls I56 will become disarranged, because theretaining holes I54 are considerably deeper than the engaging holes I56.

The power connection just described causes the carriage I25 to bereciprocated back and forth longitudinally. Every time it moves towardthe front limit of its stroke (full line position in Figs. 6, 3, 11, 15and 17), a butt plate I62, which is secured to the front end of its legI26, strikes against the rear end of the stop arm I22 and swings therock arm I08 and its pivot IIO forwardly, thereby retracting thedividing finger I I I. Thereupon, when the carriage moves rearwardly,said dividing finger pushes rearwardly such nuts as may happen to bepositioned rearwardly of it. This action thereby separates a group ofnuts from the rear end of the row of nuts on the tap shank, and movesthis group rearwardly and thereby forms a gap between this group of nutsand the row of nuts. If, for any reason, the foremost nut of the groupof nuts should be carried only partway along, and then left behind, thisnut will be returned in a forward direction when the dividing fingermoves forwardly on its idle stroke. This ensures that there will be adefinite gap between the separated group of nuts and the row of nutsleft behind, and that the rear-end of this gap will be at the front endof the group of nuts.

The numeral I63 represents a resilient stop arranged in the path of thescrew nuts adjacent to the front side of the front pair of tap grippingor holding jaws I8I, I82 which will be described more fully later on.This stop is preferably mounted on the upper end of a post I64 which hasits lower end threaded into the tailstock I04 of the main frame, asshown in Figs. 3 and 21. The stiffness or strength of the resilient stopis less than the strength of the spring I23 which operates to move thescrew nuts rearwardly on the shank of the tap. When therefore a nut ismoved rearwardly positively by the stripping mechanism, which will behereinafter described, from a position in front of the front tap holdingjaws I8I, I82 to a position in rear of the same, then the resilient stopwill yield and permit the respective nut to pass rearwardly of the tapshank. If, however, a nut is kicked rearwardly with considerable forceby the starting or dividing finger I I I owing to the momentum of therearwardly moving rock arm I08 and associated parts then this nut willbe arrested by the yielding stop and prevented from being thrown intothe mouth of the jaws I 8I, I82 while the latter are open and permittingthe same to close for holding the tap shank.

Tap gripping or holding mechanism Secured to the driving cross shaftI49, as best shown in Figs. 7 and 11, is a gripping-lever, sewingmachine cam I65. This cam operates two upright levers I66 and I66a.which are fulcrumed at their lower ends on a pivot pin I61. The latteris suitably arranged in the lower part of the tailstock I04 and ispositioned horizontally and longitudinally, thereby allowing the leversI66, I66a, to swing in parallel planes which are vertical and transverseof the machine. Anti-friction engagement of the central part of saidlevers by the sewing machine cam I is effected by providing each leverwith a suitable roller I68 which rolls in the irregular, curvilineartrack of said cam and imparts an appropriate movement to the levers.Inasmuch as both of these levers are actuated by the one cam, it followsthat their movement relatively to each other is very positive andreliable.

The upper ends of these levers I66, I66a are preferably bifurcated, asshown in Fig. 11, and are suitably slotted, as shown in Figs. 7 and 8,to receive companion thrust pins I10, I10a. Each of these pins isdisposed horizontally and longitudinally in the outer end of a companionplunger I1I I1 Ia. Each plunger is slidably arranged in a companionwedge I12, I12a, but is limited as to this sliding movement by limitingpins I13, I13a, each of which is secured at its opposite ends (see Fig.12) to its companion wedge, and is centrally received within a companionslot I14, I14a formed in the inner end of the companion plunger I1I,I1Ia.

Surrounding the inner end of the plungers I1I, I1Ia and bearing againstsuitable shoulders formed on the periphery of said plungers and in thebore of the companion wedges I12, I12a is a pair of compression springsI18, I190. Each of these springs, when fully expanded as in Fig. 7, isunder an initial heavy tension, but is restrained against any furtherexpansion by the limiting pins I13, I13a. aforesaid. This constructionenables each plunger to impose a heavy thrust against its companionwedge, but permits said in the event that an .unduly heavy opposition tomovement of the wedge is encountered.

Each wedge actuates a pair of gripping levers I15, I16 and I150, I16a,which are centrally fulcrumed on the tailstock I04 on upper pivot pinsI11, "111. and lower pivot pins I18, "811. The outer ends of said leversare resiliently urged toward each other by a pair of companion tensionsprings I80, I80a, while the inner ends of said levers are provided withupper gripping jaws I8I, I8Ia and lower gripping jaws I82, I82a. Thesejaws are secured to their companion gripping levers by upper holdingscrews I83, I83a and lower holding screws I84, I840.

The lower jaws I82, I82a have flat, upper gripping faces which areadapted to bear against flattened portions I85, I85a that are formed onthe under face of the tap shank 95. This prevents the tap from rotatingwhen either one or both of the pairs of gripping jaws are closed. Thefaces of the upper jaws I8I, I8 Ia are of concave, longitudinallycylindrical form so as to get a firm grip on the annular peripheralsurface of the tap shank, and to hold the same in accurate lateralalignment. The use of this cylindrical face on only the upper jaws isalso of advantage in the construction of the machine, as this face maybe accurately aligned with the axis of the chuck 55 and then the lowerflat faced jaws I82,

I82a brought up to bear on the lower flattened portions I85, I85a of thetap shank.

In actual practice the shanks of a tap are frequently found to be notabsolutely straight. In

.wedge to lag slightly behind (as shown in Fig. 8)

present invention by leaving enough space between the sides of the upperjaws I8I, I8Ia and the inner faces of the cheeks I88, I88a of the uppergripping levers I15, I'I5a, that said upper jaws may be positionedobliquely to properly seize a tap shank which is not perfectly straight.To effect this adjustment when the-operation of the machine indicatesits desirability, the operator slacks off the holding screw (I83 orI83a) of one of the upper jaws I8I, I8Ia and then grips the tap in theother pair of jaws. He then closes the first pair of jaws and moves theloose upper jaw until it snugly fits the shank of the tap, positioningsaid upper jaw obliquely if this is desirable. In addition to this, hemay, if it be desirable, move said loose upper jaw laterally and/or shimit up or down, and even tilt it one way or the other by using suitablewedge shaped shims. The openings in the upper gripping lever throughwhich the holding screws I83, I83a pass are, of course, sufiicientlylarge to permit of such a manipulation of the loose upper jaw relativelyto its upper gripping lever. The operator then tightens the loose, upperholding screw (I 83 or I83a as the case may be) which he had previouslyslacked oif, and the machine will then operate satisfactorily eventhough it is employing a bent tap.

It is very important that the tap be gripped firmly by each pair ofclamping jaws, to ensure that the tendency of the tap to twist does notcause a force which tends to retract either of the wedges when itscompanion gripping jaws are in closed position. This result has beenobtained in the present invention by having the final slope I81, I8Ia ofthe wedges disposed at approximately eight degrees to the axis of thewedge. Any slope appreciably greater than this will cause a forcetending to retract the wedge greater than the frictional resistancewhich opposes this movement and which results from the frictionalcontact between the outer curved ends of the gripping fingers and thewedges.-

This question only applies to the final slope of the wedge, inasmuch asit is only when the gripping levers are substantially in the closedposition of Fig. 8 that the rotative force of the tap can have anyeffect upon the companion wedge of said gripping fingers. Hence theleading slope of each wedge may be very steep, as, for instance, thecurved 45 degree slope shown in the drawings.

It is ,to be noted that the centering tongues or noses I88, I88a of thewedges have substantially parallel upper and lower faces, and also thatthe wedges are never retracted beyond the position of Fig. 7. Thisarrangement positively prevents either gripping lever from moving intothe path of the wedge, and also permits the wedges to be operatedquietly. In addition to this, the gripping levers, because of their longstraight noses I88, I88a, may be very conveniently arranged to open at auniformly accelerated rate of movement by gently merging the curve ofthe leading slope of the wedge into the fiat faces of said noses. Such auniformly accelerated movement is much more diflicult of practicableaccomplishment when there is no nose I88, I88a to separate the grippinglevers at the time when the wedges are in their retracted position.

The operation of the gripping jaws is such that at no time is the tapheld by less than one pair of gripping jaws. To accomplish this in apositive manner it is necessary that the action of the gripping jawsoverlap each other to a certain extent, i. e., at one time in the cycleof operations both gripping Jews are in gripping engagement with theshank of the tap;--then one pair of the gripping jawsis o'pened;--andthis pair is caused to again grip the shank of the tap before the otherpair of gripping jaws is opened. The correct synchronism of thisalternate movement is reliably taken care of by the one sewing machinecam I which actuates both pairs of gripping levers.

When it is desired to remove a tap which requires regrindingOrreplacement it is necessary to have both pairs of gripping jaws open.To accomplish this result the whole machine is first stopped at a pointwhere the front pair of gripping jaws IBI, I82 are open. At this timethe rear gripping jaws I8Ia, I82a are closed. To open the latter pair.of gripping jaws, the operator slacks off the holddown screw I90 whichis threaded vertically in the upper part of the tailstock I I04 andwhich normally bears downwardly upon a stop arm I 9i secured to thepivot pin I'IIa of the rear, upper gripping lever "51;. This particularpivot pin is different from the other gripping lever pivot pins III, I18and H811. in that it is provided with a central eccentric portion I92,(see Fig. 9) so that when aforesaid holddown screw ISO is slacked offand said pivot pin or eccentric pin "la is partially rotated manually bythe hand lever I93 in a counterclockwise direction (as viewed in Fig. 8)the central fulcrum of the upper rear gripping lever MM is lifted andits companion jaw I8Ia freed from the tap. The latter is then free to beremoved. To replace the new or reground tap, this whole process is, ofcourse, reversed.

Stripping mechanism of the companion upper gripping lever (H5 or Ilia)stand in the path of their companion pair of stripping fingers. When,however, either pair of gripping jaws is opened, the cheeks (I86 or3611) of their companion upper gripping lever are elevated out of thepath of said stripping fingers and the latter are enabled to engage withwhatever nuts lie in their path on the rearward stroke of the carriageI25.

In Fig. 15 is shown (diagrammatically) the stripper carriage I25 in its.retracted or forward position. In this position the dividing finger IIIhas just finished dividing a group I96 of threaded nuts II2 (the groupshown consists of two nuts) away from the row of threaded nuts on thetap shank, and has pushed this group of two nuts against the stiffresilient stop I63. Also it has left a gap between this pair or group ofnuts I and the rest of the row of nuts on the tap shank. In this Fig.15, the front pair of stripping lever cheeks I86 are shown in dottedlines, which indicates that they are open, while the rear pair ofstripping lever cheeks I86a are closed. In this position, therefore, thetap shank is being gripped only by the rear pair of gripping jaws I8Ia,182a.

In this Fig. 15 the primary stripping fingers I99, I94 have just rotatedinto their closed position under the influence of their individualcompression springs I98 and I9 and against their stop pins 200, 200a.They have thus swung into the path of the nuts on the tap shank (seealso Fig. 10) and into the gap lying just forwardly of the group of twonuts I96 which has been pushed against the stiif resilient stop I63.Because of this gap, the primary stripping fingers I93, I94 are enabledto positively and reliably move to-a position which is forwardly of thisgroup of nuts I96 just referred to, and thereby positively move saidgroup of nuts rearwardly.

The stripper carriage I25 now moves rearwardly to the position of Fig.16, causing said group of two nuts I96 to be forced by the primarystripping fingers I93, I94 past the resilient stop I63 (which is tooweak to resist this movement) and past the primary gripping jaws I6I,I92, to the position shown, which is just forwardly of the second pairof gripping jaws I8Ia, I92a.

The primary gripping jaws I8I, I92 now close, and the tap shank 95 isnow gripped by both pairs of gripping jaws, as shown in Fig. 16. Thenext movement of the stripper carriage I25 is an idle movement, as faras the primary stripping fingers I93, I94 are concerned. This movementdoes, however, actuate the dividing finger III, as will be apparent.

The rear or secondary gripping jaws I8Ia, I020 are now caused to open,as shown in Fig. 17. This enables the rear or secondary strippingfingers I93a, I94a to close a short distance behind the group of nutsI96, so that when the said secondary stripping fingers are movedrearwardly with the stripper carriage to the position of Fig. 18, theyslide this group of nuts I96 past the rear gripping jaws I 8Ia, IBM andoff the tail end of the shank of the tap, as shown, from whence theyfall through a chute I91 out of the machine.

As actually manufactured, the machine is so constructed, that thedividing finger III makes one stroke to every one stroke of thestripping carriage I25. But, each pair of stripping fingers is idle oneach rearward carriage stroke because of the interference with saidfingers of the cheeks I86, I96a of the upper clamping levers I15, "501.Hence, the dividing finger II I makes two strokes for every oneeffective stroke of the stripping fingers. For instance in Fig. 15 thedividing finger III has just brought the group of two nuts I96 upagainst the stiff resilient stop I63, this having been effected duringthe previous idle stroke of the primary stripping fingers I93, I94 andthe active, rearward stroke of the secondary stripping fingers I93a, I94a. Then, while the carriage moves rearwardly and the primary strippingfingers I93, I94 move the group of two nuts to a position just in frontof the second gripping jaws (Fig. 16), the dividing finger has picked upwhatever quantity of nuts it was able, which in this particular case'isthe single nut MI. The next stroke of the carriage I25 is idle as far asthe primary stripping fingers I93, I94 are concerned, but it will benoted that the dividing finger III has not been idle during this stroke,having picked up two more nuts 202 and added them to the single nut 20Ito form a group of these nuts (see Fig. 18) which is analogous to thegroup I96 of two nuts of Fig. 15.

Figs. 20-22 These figures illustrate a modified form of dividingmechanism. In this case the rock arm I06 of Figs. 1-19 has beeneliminated and replaced by a carriage 203 which is adapted to slidelongitudinally on a pair of horizontal, longitudinal slide bars 204.Said carriage is resiliently urged rearwardly by a pair of compressionsprings 205 which encircle their companion slide bars 204 and bear attheir rear ends against said carriage 203 and at their front endsagainst a pair of collars 206 secured by set screws 20'! to theircompanion slide bars.

Pivoted at 208, 209 to said carriage are a pair of dividing or startingfingers I I-I.I which are disposed on opposite sides of the tap shank95.I in a horizontal plane. gers is resiliently urged by a compressionspring into contact with the nuts I I2.I on said tap shank.

Actuation of said carriage is effected by the stripping carriage I25.Iwhich on every forward stroke bears with its butt plate I62.I againstthe rear end of the adjustable thrust screw 2 l which is suitablythreaded through an ear 2 in the carriage 203 and locked in place by alock nut 2I2.

The action of these dividing fingers III.I is very similar to the actionof the stripping finger I II of Figs. 1-19 except that the use of thesedual stripping fingers III.I is somewhat more smooth and positive inaction in that any tendency of the nuts to cook on the tap shank 95.I ismuch less likely to occur, and the transverse pressures against theoutboard" or front end of the tap are balanced.

Figs. 23-27 These figures illustrate, diagrammatically. still anotherform of dividing finger III.2. In this case said pair of dividingfingers is formed similarly to the pairs of stripping fingers of Figs.l-19, and is similarly pivoted to a companion leg I261, I2'I.2 of astripper carriage I25.2. In this type of construction, however, it hasbeen deemed advisable to provide additional means of ensuring that theprimary stripping fingers I931, I94.2 will close in a gap located infront of the group of nuts I96.2 about to be pushed rearwardly by saidprimary stripping fingers. This means consists of a detaining spring2I3, which is located in front of, and is similar in construction to,the resilient stop l63.2, and is adapted to prevent any nut or nuts frombeing moved rearwardly except such as have beenvery securely grasped bythe dividing fingers III.'2. It has been found in actual practice thatall types of dividing fingers will occasionally get a weak grip on onecertain nut, and in such an event, said weakly gripped nut may be movedforwardly just far enough to interfere with the primary strippingfingers I93.2, I94.2 opening in a gap or vacant space behind the groupof nuts I 96.2 to be vmoved. By the use of the detaining spring 2I3, anysuch insecurely held nut is restrained against further rearward movementand is freed from the dividing fingers I I L2 and is then retractedforwardly by said dividing fingers as the latter return in a forwarddirection with the stripping carriage I25.2.

By this arrangement any nuts moved rearwardly by the dividing fingersIII.2 are either positively moved into the space between the detainingspring 2I3 and resilient stop I612, or are returned in a forwarddirection to the row of nuts on the front end of the shank of the tap.

Hence when the stripping carriage I25.2 moves from the position of Fig.23 to that of Fig. 24, the primary stripping fingers I93.2, I94.2 areenabled to reliably close in a gap located forward of the group of nutsI96.2 and to positively move Each of these dividing fin-' till dill

lid

them rearwardly past the open primary gripping levers "5.2, "8.2 and infront of the closed secondary gripping levers.

It is to be understood that when once the primary stripping fingers"3.2, l9l.2 have positively engaged the front face of the group of nuts"8.2, no trouble is experienced by the secondary stripping fingers.inasmuch as the required gap or vacant space has already been formed,and the machine is designed sothat the strokes of the two pairs ofstripping fingers overlap each other sufllciently to ensure continuous,high speed and reliable movement of the groups oi nuts along the tapshank.

These diagrammatic Figs. 23-27, similarly to diagrammatic Figs. 15-19,illustrate how the dividing fingers L2 make two eiiiective strokes forevery one eflective stroke of the stripping fingers. For instance in therearward stroke of the stripping carriage from Fig. 23 to. 24 only onenut was moved rearwardly hy the dividing fingers lil.2 past thedetaining spring iii. Then the next rearward stroke from Fig. 2% to Fig.it moved two nuts rearwardly past said detaining spring, making, in thiscase, a group of three nuts to he carried rearwardiy hy the strippinglingers instead of the group litd of two nuts which were movedrearwardly hy the stripping fingers during the previous cycle ofoperations.

In this construction, lust as in the construction of gs. l-lil, eachpair of stripping fingers is prevented from engaging with whatever nutsare positioned forward of their companion pair of griing levers hy thecheeks ltd and iiiia of said levers.

l lies. ii-iZ These figures illustrate a modified form of pusheractuating mechanism, replacing the curvilinear heart-shaped cam ii ofdig. a, lay a. pair of straight faced cams it'll. Those cams are securedlay a pair of hoitsi ii to a drive carriage i l t which is verticallyslidahle on a pair of slide bars The latter are secured in upper andlower hrackets ill, tilt of the main frame tillii of the machine, andare held in place by upper and lower hinding nuts lift, iii.

dlidahly arranged on a horizontal longitudinal iltliliit in the upperfront part of the machine is the usual pusher sleeve lilil upon which ismounted a pair of thrust, anti-friction rollers "it The latter engagethe rear surfaces iii and tilt of the cams lull and cause the pushersleeve to reciprocate hack and forth as the carriage ii i ii is moved upand down, retraction of the pusher carriage helng effected lay asuitably compression spring iiii. When said carriage commences to rise.the rollers lid are in contact with the upper flat surfaces iii of thecams ltd. These surfaces are very steep, and hence the rearward movementof the pusher carriage lid is very rapid. This causes the pusher torapidly move the lowermost nut from the vertical alignment channel tothe front end of the threaded hit of the top (not shown) The rollersillfii then come into contact with the lower straight cam faces fill ofthe s liki and, as these faces are much steeply pitched than the uppercam faces W2, it follows that the pusher hit is caused to now moveslowly, rearwardiy so as to effect a proper rate of cutting speed. It isevident that the cams lid, because of their flat faces i22 and 223, canhe so machined as to provide both a very rapid initial rearward movementof the pusher,

and an extremely accurate cutting movement of said pusher.

Secured to and depending from the drive carriage 2|! is a rack 224 whichmeshes with a pinion gear 225 rotatably mounted on a shaft 225 which isjournaled horizontally and transversely on the machine. This shaft 228is constantly driven in one direction by the main driven pulley wheel45.3 by intermediate gearing which is deemed not necessary to beillustrated. Secured to said shaft by a transverse pin 22'! is a drivecollar 223 which is rotatably connected through splines 228 with aclutch collar 230, having ratchet-shaped clutch teeth 23 I at its inner,vertical end. These teeth are adapted to engage with an annular row ofsimilar ratchet-shaped, driven clutch teeth formed on the adjacent endof the huh 232 of the pinion Zlld. Thus as the clutch collar 230 ismoved to the right, as viewed in Fig. 29, its driving clutch teeth iiiengage with the clutch teeth of the pinion huh lit and cause the piniongear 22$ to drive the rack iii and the drive carriage 2ft upwardly. Whensaid clutch collar lid is moved to the left, as seen in Fig. 29, thelifting force upon said drive carriage lid is released and said carriageis jerked downwardly by a pair of suitably arranged tension, returnsprings Md.

Formed centrally on the clutch collar fit is a pair of annular flangesiii, iii hetween which is received a roller iti. The latter is journaledon the upper arm of a bifurcated hell crank iii which is fulcrumed atlid on the main frame tilt of the machine. pivoted at iii to thehorizontal arm of said bell crank ill is a yoke fit. The latter issecured by a pin iii to the lower end of a vertical control screw itfwhich is vertically movable relatively to the main frame lilfi of themachine, being somewhat loosely received at its upper end within a slidehearing iii! arranged in said main frame s screw has two limitingpositions, an upper position when the driving clutch teeth iii aredisengaged, and a lower position when said clutch teeth are engaged.This screw iii is resiliently held in either its upper or lower position"by a suitable pawl iii actuated icy a compression spring iii, andhaving a pointed nose which is adapted to engage with either an uppernotch hill or a lower notch il il iii Then when the drive carriage 2 illis jerked down hy its tension springs dill said lug iii strikes thelower actuating nut iii and engages the drive to again elevate the drivecarriage fill.

,Should any part of this mechanism or any other mechanism on the machinebecome jammed, the power to the entire machine is cut off, by a frictionactuated safety clutch iii. The latter is mounted on the main driveshaft its of the machine and frictionally connects the hub of the drivenpulley wheel iii to said drive shaft tit through the instrumentality .ofa compression spring iii which serves to provide the necessaryfrictional resistance.

Figs. 33-35 These figures illustrate a modified form of till

